Direct Numercal Simulation of two-phase turbulent boundary layer over waved water surface O. A. Druzhinin, Yu.I. roitskaya Institute of Applied Physics RAS, Nizhny Novgorod, Russia Data on droplets generation by the wind by Andreas et al. (2010, JGR) Droplet number density at different wind speeds at heights from 1 to 2m. Typical high-speed video image showing spray droplets shed by a breaking wave, captured at 200 Hz. Lab experiment by Fairall et al. (2009 JGR) Droplet volume concentration for wind speed 16m/s at different heights OBJECTIVE In this work the detailed structure and statistical characteristics of a turbulent, droplet-laden air flow over waved water surface are studied by direct numerical simulation (DNS). Two-dimensional water wave with wave slope up to ka = 0.2 and bulk Reynolds number Re = is considered. Droplet mass concentration 0.16 is attained (up to 16 x 10 6 drops of 100m are considered). The shape of the water wave is prescribed and does not evolve under the action of the wind and/or drops. The full, 3D Navier- Stokes equations including the impact of discrete drops and the equations of motion of individual drops are solved simultaneously in curvilinear coordinates in a frame of reference moving the phase velocity of the wave. The shear driving the flow is created by an upper plane boundary moving horizontally with a bulk velocity in the x-direction. Schematic of numerical experiment c=0.05 wave celerity ka = 0.2 wave slope GOVERNING EQUATIONS Re = Forcing of the air flow by the drops - drop coordinates - grid node coordinates - weighting factor - bulk flow Reynolds number - drop Reynolds number Equations of motion of individual drop: = 1000 water/air density ratio, N d total number of drops -drop volume - Froude number Air-flow equations: of motion CURVILINEAR COORDINATES Mapping over : BOUNDARY CONDITIONS Top plane: Bottom plane: All fields are x and y periodic Drops falling on the water are re-injected in the vicinity of the wave crests in the buffer region with velocity = air flow velocity Instantaneous vorticity modulus and drops coordinates fields: side view at y=0 Instantaneous vorticity modulus and drops coordinates fields: front view at x = 3 Instantaneous vorticity modulus and drops coordinates fields: top view at z=0.04 Trajectory of individual drop for 100< t